1. Field of the Invention
The invention relates to multifunctional monomers, to methods of producing or synthesizing such monomers, and to the use and application of such monomers as commercial products and compositions, including, for example, monomer-based products (e.g., inks, adhesives, coatings, sealants or reactive molding) and polymer-based products (e.g., fibers, films, sheets, medical polymers, composite polymers and surfactants).
Specific embodiments are directed to multifunctional methylene malonate and methylene beta-ketoester monomers but the principles disclosed herein are relevant to other disubstituted vinyl compounds having electron withdrawing groups in the beta position.
2. Background
Methylene malonate monomers, methylene beta-ketoester monomers and their associated monomeric and polymeric-based products would be useful in both industrial (including household) and medical applications. Indeed, unlike many other monomers, these monomers and their products can be produced via sustainable routes as well as be designed to be environmentally benign, biologically benign and as such many of the products can be generally regarded as “green.”
Methylene malonate monomers and methylene beta-ketoester monomers have the potential to form the basis of a large-scale platforms of new raw materials for the generation of a wide variety of new chemical products, including inks, adhesives, coatings, sealants, moldings, fibers, films, sheets, medical polymers, composites, surfactants and the like. While the production of monofunctional methylene malonates by various processes has been known for many years, these earlier methods suffer significant deficiencies that preclude their use in obtaining viable monomers for commercial exploitation. Such deficiencies in these older methods include unwanted polymerization of the monomers during synthesis (e.g., formation of polymers or oligomers or alternative complexes), formation of undesirable side products (e.g., ketals or other latent acid-forming species which impede rapid polymerization), and degradation of the product, insufficient and/or low yields, and ineffective and/or poorly functioning monomer product (e.g., poor adhesive characteristics or other functional characteristics), among other problems. The overall poorer yield, quality, and chemical performance of the monomer products formed by prior art methods impinges on their practical use in the production of the above commercial and industrial products. No viable solutions to solve the aforementioned problems have yet been proposed, accepted and/or recognized and certainly do not exist currently in the industry.
In the art, numerous attempts overall have been made to functionalize highly activated disubstituted vinyl monomers, particularly cyanoacrylates. Cyanoacrylate adhesives are one-part solvent-free adhesives that cure rapidly through polymerization at room temperature. These adhesives are used in a wide range of applications across various industries as a result of their fast and often strong shear strength. Unfortunately, while the cyanoacrylic anionic cure mechanism is facile, poor impact and environmental resistance has vastly limited their potential from the broad array of applications that thermosetting systems allow. For example, thermosetting systems provide the benefits of cross-linking and allow for a particular physical or chemical trait to be introduced via a multifunctional resin. While attempts have been made to produce multifunctional systems for cyanoacrylates they have not been met with any commercial success due to poor yields, poor stability and high costs. Monomeric systems in the prior art either go through a blocking agent process, the incorporation of a secondary cure or similar processes. Multifunctional cyanoacetates converted to cyanoacrylates simply cannot be cracked to monomer the same way that a monofunctional cyanoacrylate monomer is made now.
Conversely, while their cure is slower, crosslinked epoxies, polyurethanes, polyesters, silicones polyimides, polyureas and the like provide excellent properties but require heat and/or mixing and relatively long cure times that are energy intensive to polymerize. Multifunctional acrylic systems polymerize quickly, but only at high catalyst loading, and/or through the use of external energy sources or primers.
The prior art's attempts at delivering a multifunctional system have been met with no commercial success and require long cure times for ultimate strength and display poor stability due the use of an allylic functionality. The prior art also cannot deliver the wide range of properties that a functionalized resin can nor can deliver a functionality greater than 2 as described in the art.
Accordingly, it would of great utility if multifunctional 1, 2 substituted methylene malonates and methylene beta-ketoesters could be produced not only as reactive monomers but also incorporated as reactive groups along oligomeric and polymeric backbones. It would be of even further use to not only employ such monomers, oligomers and polymers as polymerizable molecules, but to also functionalize them for other purposes, such as conducting chemistry on the methylene malonates to create other functional groups, such as dyes, catalysts, chelating agents, medicals, anti-fungal agents and the like or to polymerize off of them other monomers to create not a crosslinked system but alternatively a unique copolymer system, such as a polyolefin off of certain parts of a polyester.
Also of utility would be the ability to use a process for easily producing certain base methylene malonate monomers or methylene beta-ketoester monomers and then to use a second process to convert those into more complex, difficult to produce and/or higher molecular weight methylene malonate monomers or methylene beta-ketoester monomers.
Thus, multifunctional monomers, i.e. monomers having two or more methylene double bonds, would be of interest as they could be selectively functionalized or crosslinked. No viable routes to multifunctional methylene malonate monomers have yet to be proposed, accepted and/or recognized and certainly do not exist currently in the industry.
Further, a need exists for methods for synthesizing methylene malonate monomers and methylene beta-ketoester monomers and others that are capable of being viably used in commercial and industrial applications.